A NEW SUPERCONVERGENT RECOVERY METHOD FOR FE ANALYSIS ON STRUCTURAL FREE VIBRATION PROBLEMS

This paper presents a new superconvergent recovery method for the finite element analysis on structural free vibration problems. Based on the superconvergence properties on frequencies and nodal displacements in modes, a linear ordinary differential boundary value problem (BVP) is set up, which approximately governs the mode on each element. This linear BVP is solved by using a higher order element from which the mode on each element is recovered. Then by substituting the recovered mode into the Rayleigh quotient, the frequency is recovered. This method is simple and direct. It can enhance the accuracy and convergence order of the frequencies and modes significantly with small computation. Numerical examples demonstrate that this method is efficient, reliable and potential.